Pump

ABSTRACT

A small solids handling pump of the type for use in pumping mixed liquor or raw sewage, comprising: an elongated vertically extending hollow standard; a volute housing affixed to the lower portion of the standard having an inlet opening through a bottom portion thereof; motor means positioned above the upper end of the standard; an impeller positioned within the volute housing immediately above the inlet opening; and a shaft extending through the standard interconnecting the impeller to the motor means such that rotation of the impeller results in a vortex immediately below the inlet opening so as to centrifugally exclude large solids from entering the volute housing through the inlet opening. The diameter of the inlet opening is in the range of .4 to .7 times the diameter of the impeller.

United States Patent 3/1967 Japan 415/170 A W65 June 4, 1974 [54] PUMP 916,670 11/1921 Switzerland 415/219 Inventor: ank G. Weis, Ka sas City, Mo. 808,796 5/1951 Germany 415/131 [73] Assignee: Ecodyne Corporation, Chicago, 111. Primary Examiner-C. ,l. Husar [22] Filed: Mar. 18, 1971 Attorney, Agent, or Firm-Joel E. S1egel; Charles M,

Kaplan [211 Appl. No.: 125,667

. ABSTRACT [52] 11.8. C1 417/424, 415/131, 415/121, A small solids handling pump of the type for use in 415/219 pumping mixed liquor or raw sewage, comprising: an [51] Int. Cl. F041) 17/00 elongated vertically extending hollow standar a [58] Field of Search 417/424, 30, 38, 40; lute housing afiixed to the lower portion of the stan- 415/131, 213 A, 213 R, 501, 219 dard having an inlet opening through a bottom portion thereof; motor means positioned above the upper end [56] References Cited of the standard; an impeller positioned within the vo- UNITED STATES PATENTS lute housing immediately above the inlet opening; and I a shaft extending through the standard interconnecting the impeller to the motor means such that rotation 2:839:006 6/1958 7/424 of the impeller results in a vortex immediately below 2,850,982 9/1958 Fabrin 417/424 the inlet Opening 50 as centrifugally eXclude large 2,884,862 5/1959 N1lSn 415/213 solids from entering the volute housing through the 2,930,325 3/1960 Beard et a1. 417/424 inlet opening. The diameter of the inlet opening is in 3,256,828 6/1966 Rule..: 417/424 the range of ,4 to ,7 times the diameter of the impel- FORElGN PATENTS OR APPLICATIONS 452,706 11 Claims, 3 Drawing Figures PUMP BACKGROUND OF THE INVENTION This invention relates to a small solids handling pump and more partcularly to a pump designed to efficiently pump raw sewage or mixed liquor from a sewage treatment plant at a low flow rate. I

Heretofore, it has taken pumps with a minimum passage size of 2 /4 to 3 inches to handle raw sewage or mixed liquor. Pumps having a smaller passage size have tended to clog the impeller. These pumps cannot efficiently or economically, if at all, handle flows in the range of O to 100 gpm. Only pumps with passage sizes of approximately /2 inches can efficiently perform at these low flow rates.

SUMMARY OF THE INVENTION The present invention provides a pump having a small passage size capable of handling raw sewage or mixed liquor.

The primary object ofthe present invention is to provide a pump capable of handling raw sewage or mixed liquor at low flow rates.

Another object is to provide a pump for use in handling raw sewage or mixed liquor that permits only small solids to enter through the inlet opening.

A further object is to provide a pump for use in handling raw sewage or mixed liquor having a small passage size that is not vulnerable to clogging.

A still further object is to provide a pump that minimizes the side thrust on the impeller and therefore does not require a lower bearing. I

Another object is to provide a pump that permits easy access to the volute housing and removal of the impeller therefrom for maintenance.

The pump of the present invention provides an impeller affixed to the lower end ofa vertically extending motor shaft. The impeller is positioned within a volute housing having an inlet opening through a bottom portion thereof. The impeller is a semi-open type with radial vanes extending from the shaft hub to the outer periphery of the impeller. The inlet opening is within the range of 0.4 to 0.7 times the diameter of the impeller so that a large part of the impeller is exposed through the inlet opening. Upon rotation of the impeller a vortex results immediately below the inlet opening which centrifugally excludes large solids, rags, paper stringy material, etc., that are too large to pass through the pump. The volute housing is round in horizontal cross section so there is a balanced side thrust on the impeller which makes it unnecessary to have a bottom bearing near the impeller.

Other objects and advantages will be apparent from the following description when read in connection with the accompanying drawing in which:'

DESCRIPTION OF THE DRAWING FIG. I is an elevational view ofa pump assembly embodying the concepts of the present invention, certain parts being broken away and in section to reveal details of construction;

FIG. 2 is a bottom view of the pump assembly illustrated in FIG. I; and

FIG. 3 is an enlarged side elevational view of the volute housing of FIG. 1, broken away to show details of the impeller and suction cover.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawing, and particularly to FIG. 1, a vertical shaft centrifugal pump assembly incorporating features of the present invention is illustrated generally at 10. Pump it) includes a vertically extending hollow standard 12 having an upper section 14 and a lower section 16. Section 14 has an upper base portion 15 formed integral therewith upon which an electrical motor is mounted in a conventional manner, as by bolts 22. Discharge opening is positioned a short distance below base portion 15 and is in fluid communication with the interior of standard 12.

Volute housing is formed integral with the lower end of section 16 and is in fluid communication therewith. Housing .30 is round when viewed in horizontal cross section, as seen in FIG. 2. A large diameter circular access opening 32 is centrally disposed through the bottom portion of housing 30. A suction cover plate 35, having an inlet opening 37 therein, is removably mounted to the bottom portion of housing 30, as best seen in FIG. 3. Cover plate includes an inner ring portion 38 whose outer side periphery snugly fits adjacent access opening 32 so as to effectively reduce the open area through the bottom portion of housing 30. An outer ring portion 39,'formed integral with ring 38, is bolted to the bottom portion of housing 30 by bolts 40. Discharge opening 25 may alternatively be disposed through a portion of housing 30.

Shaft 42, extending through standard 12, has its upper end attached to motor 20 for rotation about a substantially vertical axis and its lower end to an impeller 50, positoned within housing 30. Associated with the upper portion of shaft 42 is a conventional bearing and seal arrangement 44 to prevent liquid passing through standard 12 from entering motor 20. Impeller 50 comprises a circular plate portion 52 formed intergral with a central shaft hub portion 54 attached to the lower end of shaft 42. A plurality of radial impeller vanes 56 attached to the underside of plate 52 extend from hub 54 to the outer periphery of plate 52, as seen in FIGS. 2 and 3. Vanes 56 may be straight or curved and are preferably approximately one-fourth to onehalf inches in height so as to permit efficient handling of low flow rates, i.e., 0 to 100 gpm.

An important feature of the present invention is the positioning of impeller 50 with respect to inletopening 3'7 and the relative diameter of inlet opening 37 with respect to the diameter of impeller 50. Impeller 50 is positioned within housing 30 such that the bottom of vanes 56 are aprpxoimately 0.01 inches above the top surface of ring 38. The diameter of inlet opening 37 is in the range of 0.4 to 0.7 times the diameter of impeller 50 such that upon rotation of shaft 42 and impeller 50 by motor 20 a vortex results immediately below inlet opening 37 so as to centrifugally exclude large solids from entering housing 30 through inlet opening 37.

As mentioned above, housing 30 is circular in horizontal cross section so to result in a balanced side thrust against impeller 50 and therefore removes the necessity of a lower bearing around shaft 42. The diameter of access opening 32 is greater than the diameter of impeller 50 so as to permit removal of impeller 50 from housing 30. Upon removal of suction cover plate 35 by loosening bolts impeller may be dropped through access opening 32 after removal of same from shaft 42.

In operation, pump is submerged in the liquid to be pumped,i.e., mixed liquor or raw sewage, such that inlet opening is below the surface thereof. Upon rotation of impeller 50 a suction is created at the inlet opening 37 causing liquid to flow therethrough' into housing 30 and then up standard 12 and out discharge opening 25. Immediately below inlet opening 37 a vortex of the liquid being pumped results which centrifugally excludes large solids, rags, paper, stringy material etc., from entering housing 30 through inlet opening 37. This permits pump 10 to handle liquid of the aforedescribed type even though it has a passage size of approximately one-half inch and thus is able to efficiently operate at relatively low flow rates.

Some of the advantages derived from the present invention will be apparent from the following test example. A pump of similar construction to that shown in H68. 1 to 3 was placed in a test tank containing domestic sewage obtained from the city of Lenexa, Kansas. The test pump 10 employed a motor 10 rated at one-half horsepower and 1,750 rpm, an imepller 50 having a 7 inch diameter and 16 radially extending vanes 56 of one-fourth inch in height, and an inlet opening 37 of 3% inches in diameter. Inlet opening 37 was positioned approximately 6 inches below the surface of the sewage. Upon rotation of impeller 50 the sewage was drawn up through inlet opening 37 into housing 30 and then out discharge opening 25 at a flow rate of 10 gpm. A vortex was visible below the surface of the sewage which centrifugally excluded large solids from entering inlet opening 37 and thus prevented clogging of the impeller. h a

While the embodiment described herein is at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.

What is claimed is:

l. A small solids handling pump of the type for use in pumping mixed liquor or raw sewage, comprising:

a. an elongated vertically extending hollow standard;

b. a volute housing affixed to the lower portion of said standard having an inlet opening through a bottom portion thereof;

0. motor means positioned above the upper end of said standard;

d. impeller means positioned within said volute housing immediately above said inlet opening; and

e. shaft means extending through said standard interconnecting said impeller means to said motor means such that rotation of said impeller means results in a vortex immediately below said inlet opening so as to centrifugally exclude large solids from entering said volute housing through said' inlet opening.

2. The invention of claim 1 wherein a discharge opening is positioned a short distance below the upper end of said standard.

3. The invention of claim 1 wherein a discharge opening is positioned through a portion of said volute housing.

4. The invention of claim 3 wherein bearing means and mechanical seal means are provided above said discharge opening so as to prevent liquid from entering said motor means. i

5. The invention of claim 1 wherein said volute housing is round in horizontal cross section so as to result in a balanced side thrust and thus removes the necessity for lower bearing means.

6. The invention of claim 1 wherein said impeller means is of the semi-open type having a plurality of radial vanes extending from a shaft hub to the periphery of said impeller means.

7. The invention of claim 1 wherein the diameter of said inlet opening is in the range of 0.4 to 0.7 times the diameter of said impeller means. 7

8. A small solids handling pump of the type for use in pumping mixed liquor or raw sewage, comprising:

a. an elongated vertically extending hollow standard having a discharge opening therein;

b. a volute housing affixed to the lower portion of said standard having an access opening through the bottom portion thereof;

c. suction cover plate means having an inlet opening therein removably mounted to said bottom portion of said volute housing so as to effectively reduce the open area through said bottom protion of said volute;

d. motor means positioned above the upper end of said standard;

e. impeller means positioned within said volute housing immediately above said inlet opening; and

f. shaft means extending through said standard interconnecting said impeller means to said motor means such that rotation of said impeller means results in a vortex immediately below said inlet opening so as to centrifugally exclude large solids from entering said volute housing through said inlet opening.

9. The invention of claim 8 wherein said access opening is sized so as to permit said impeller to pass therethrough upon removal of said suction cover plate means.

10. The invention of claim 8 wherein the diameter of said inlet opening is in the range of 0.4 to 0.7 times the diameter of said impeller means.

11. The invention of claim 10 wherein said impeller means is positioned approximately 0.01 inches above said suction cover plate means.

P0405) UNITED STATES PATENT OFF ICE 569 CERTIFIEATE OF CORRECTION Patent N 3 8l4,55 l Dated June 4 1974 Inventor(s) Frank G. Weis It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 6, please change "partculafly" to -particularly--.

Column 2, line 53, please change "aprpxoima tely" to "approximately".

Column 3, line 23, please change "imepller" to "impeller",

Column 4, line 34, please change "protion" to --p0rtion-.

Signed and sealed this 15th day of October 1974,

(SEAL) Attesc:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. A small solids handling pump of the type for use in pumping mixed liquor or raw sewage, comprising: a. an elongated vertically extending hollow standard; b. a volute housing affixed to the lower portion of said standard having an inlet opening through a bottom portion thereof; c. motor means positioned above the upper end of said standard; d. impeller means positioned within said volute housing immediately above said inlet opening; and e. shaft means extending through said standard interconnecting said impeller means to said motor means such that rotation of said impeller means results in a vortex immediately below said inlet opening so as to centrifugally exclude large solids from entering said volute housing through said inlet opening.
 2. The invention of claim 1 wherein a discharge opening is positioned a short distance below the upper end of said standard.
 3. The invention of claim 1 wherein a discharge opening is positioned through a portion of said volute housing.
 4. The invention of claim 3 wherein bearing means and mechanical seal means are provided above said discharge opening so as to prevent liquid from entering said motor means.
 5. The invention of claim 1 wherein said volute housing is round in horizontal cross section so as to result in a balanced side thrust and thus removes the necessity for lower bearing means.
 6. The invention of claim 1 wherein said impeller means is of the semi-open type having a plurality of radial vanes extending from a shaft hub to the periphery of said impeller means.
 7. The invention of claim 1 wherein the diameter of said inlet opening is in the range of 0.4 to 0.7 times the diameter of said impeller means.
 8. A small solids handling pump of the type for use in pumping mixed liquor or raw sewage, comprising: a. an elongated vertically extending hollow standard having a discharge opening therein; b. a volute housing affixed to the lower portion of said standard having an access opening through the bottom portion thereof; c. suction cover plate means having an inlet opening therein removably mounted to said bottom portion of said volute housing so as to effectively reduce the open area through said bottom protion of said volute; d. motor means positioned above the upper end of said standard; e. impeller means positioned within said volute housing immediately above said inlet opening; and f. shaft means extending through said standard interconnecting said impeller means to said motor means such that rotation of said impeller means results in a vortex immediately below said inlet opening so as to centrifugally exclude large solids from entering said volute housing through said inlet opening.
 9. The invention of claim 8 wherein said access opening is sized so as to permit said impeller to pass therethrough upon removal of said suction cover plate means.
 10. The invention of claim 8 wherein the diameter of said inlet opening is in the range of 0.4 to 0.7 times the diameter of said impeller means.
 11. The invention of claim 10 wherein said impeller means is positioned approximately 0.01 inches above said suction cover plate means. 